Why would you breed them and then either give or sell them to a pet store so they can be snake food? If you're lucky a couple will be pets. Of those couple some people will get bored with them and they'll be mistreated. In my area the zoo buys a LOT of rats for food, not just mice.
I'm sure I'm missing something here.
This reminds me of something I posted on the dog board a while ago. A woman was breeding her dog so her children could experience the miracle of birth. If they follow the puppies and their puppies they'll also experience the miracle of abandonment and death.
Maybe I'm missing something - tell me what it is.